Expansion tube for liquid gas systems



NOV. 1, 1932. $1 5, THOMAS 1,885,644

EXPANSION TUBE FOR LIQUID GAS SYSTEMS Filed May 1, 1931 I a I I/I/ Patented Nov. 1, 1932 UNITED STATES PATENT! OFFICE STEPHEN S. THOMAS, OF LEBANON, OHIO EXPANSION TUBE FOR LIQUID GAS SYSTEMS Application filed May 1, 1931. Serial No. 534,425.

This invention relates to expansion tubes for liquid gas systems, and its principal object is to provide an expansion chamber between the source of liquid fuel supply and the gas regulator or expansion valve to facilitate the conversion of the liquid fuel .into gaseous form before reaching the gas regulator or expansion valve. The present ex pansion tube is particularly suitable for use in connection with liquefied carbon gases,

such as propane or butane or a mixture thereof, so that the same may be automatically expanded and safely used in ordinary heaters, such as gas stoves, wlthout alteration thereof.

Liquid gas of this character expands readily at ordinary house temperature, and 1n order to have a constant supply of gas at the gas regulator or expansion valve, I have provided one or more expansion tubes between the storage tank and the gas regulator or expansion valve wherein is employed a series of fine mesh screens by means of which the liquid fuel is broken up into very small particles, thus facilitating the rapid conversion thereof into gaseous form.

Another object is to provide an expansion tube of novel construction wherein the liquid fuel is repeatedly broken up during its passage through the tube, so that by the time it reaches the gas regulator or expansion valve, it has been converted into gaseous form. Another object is to eliminate the necessity for any heating means for dissipat- 5 ing the extreme cold which usually results from the expansion of the gas and interferes with its successful use.

The invention consists, therefore, in the several novel features hereinafter fully set forth and claimed.

An exemplification of the invention is illustrated in the drawing accompanying this specification in which- Figure 1 is a view, partly in side elevation and partly in vertical longitudinal section, of a system embodying a plurality of expansion tubes containing the present invention;

Fig. 2 is a horizontal section taken on the line 2 of Fig. 1; and

Fig. 3 is a detail enlarged fragmental section of one of the screens employed in the expansion tube.

Referring to said drawing, the reference character 5 designates a liquid fuel tank or cylinder which is filled or partially filled with liquid fuel under pressure generated therein from ordinary house temperature. Extending from the bottom of the tank or cylinder 5 is a valve controlled pipe 6 which conducts the liquid fuel to a pressure regulating valve 7 from which the liquid fuel discharges at a reduced pressure. Ordinarily, a pressure of approximately seventy pounds is developed in the tank 5 at normal house temperature and the pressure regulating valve 7 is usually set to discharge the liquid fuel therefrom at about four pounds pressure or thereabouts. The pressures mentioned are not material to the invention, broadly considered, but are given for the purpose of illustration only.

Connected with the discharge end of the pressure regulating valve 7 is one of the expansion tubes 8 which forms the subject matter of the present specification. From the discharge end of the expansion tube leads a. pipe 9 which may run to the gas regulator (seen at 10), particularly in situations where only one heater or stove is used in the system, but where more heaters or stoves are used, it is preferable to employ two or more of the expansion tubes, and, in the drawing, two such tubes are illustrated, the second one being designated by the reference character 11. In this case, the pipe 9 communicates with one end of the expansion tube 11 and a pipe 12 connects the other end of the expansion tube 11 with the gas regulator or expansion valve 10. It will be understood that the expansion valve 10 further reduces the pressure of the gas and regulates the flow thereof to the heater or other apparatus where the gas is to be consumed.

A gas regulator or expansion valve of the character illustrated is more fully shown and described in my co-pending application, filed September 14, 1929, under Serial No. 372,673. This exact construction of the gas regulator is not essential to my invention, broadly considered, as it may assume Various forms. Briefly, a gas regulator or expansion valve, as used herein, comprises an expansible and contractible chamber through which the gas flows and a valve controlled by the expansible and contractible chamber for regulating the pressure of the gas discharged from the gas regulator, whereby a steady and even flow 'of gas at a constant low pressure may discharge from the gas regulator to the gas burners when open.

The expansion tubes illustrated are substantially similar in construction, and, for this reason, I shall proceed to describe one of them in detail, it being understood that such description applies to both. The expansion tube 8 comprises an elongated tube or cylinder 13 closed at its ends by heads 14 and 15 welded or otherwise secured thereto. The head 14: is provided with a threaded tubular neck 16 which is secured to the discharge end of the pressure regulating valve 7 and the head 15 is similarly provided with a threaded neck 16 which is connected to the pipe 9 or the pipe 12 by a coupling nut 17.

Within the tube 13 is a series of disk-like screens 18 composed of very fine wire mesh, the edge portions of which are clamped between inturned flanges 19 and 20 that are formed on clamping rings 21 and 22 which are securely held in the tube. Each pair of clamping rings comprises inner and outer initially tapered rings (see Fig. 3), the outer one of which bears tightly against the inner face of the tube, and against the outer face of the inner ring. Each pair of clamping rings with the screen held between the inturned flanges thereof is inserted into the tube and forced to the proper position therein, the inturned flanges gripping the edges of the screen between them and securely holding the screens in the located positions by reason of the frictional engagement of the outer rings with the inner faces of the tube. Desirably, two fine mesh screens are associated with each pair of clamping rings, as shown in Fig. 3- When two expansiontubes are used in the system, the outlet end of one is connected to the inlet end of the other by the pipe 9, and the outlet end of said other one is connected to the gas regulator 10 by the pipe 12, to form a continuous conduit from the tank 5 to the gas regulator or expansion valve.

In the operation of the system, the liquid fuel flows from the tank 5 as the result of the pressure which is developed therein, due to ordinary room temperature, and passes through the pressure regulating valve 7 from which it is discharged at a reduced pressure into the adjacent or inlet end of the expansion tube 8. The liquid is discharged against the first screen of the series where the liquid is broken up more or less by the screen. As

the liquid fuel enters the expansion tube, it expands, and as it passes through the successive screens the liquid is checked in its forward movement and is further broken up and further expanded and is converted into gaseous form, so that by the time it reaches the discharge end of the expansion tube, the liquid fuel has been converted into a gas ready for consumption in the heater or other stove. However, as has been explained, in case several heaters or stoves are supplied from the same tank, it is preferred to use a plurality of expansion tubes in order that the liquid fuel may be completely converted into gas by the time it reaches the gas regulator or expansion valve 10. A pressure of about four pounds or thereabouts is thus developed in the expansion tubes, and in the pipe leading therefrom, which pressure is reduced to a few ounces by the gas regulator or expansion valve 10 in passing to the burners of the heater or stove.

It is to be understood that when one or more gas burners of the heater or stove are opened, the gas will flow to the gas burners, owing to the pressure developed in the system, and that when all of the gas burners are shut off, the gas regulator or expansion valve 10 will automatically shut off the flow of gas therethrough, due to the back pressure of the gas from the burners. As a result, the pressure regulating valve 7 will also close, thereby stopping the flow of liquid fuel from the tank 5. It will be observed, therefore, that a supply of gas is always present at the gas burners ready for use.

The walls of the expansion tubes are composed of relatively light gauge material which allows the normal temperature of a dwelling to dissipate the extreme cold which is developed as the fuel expands and passes through the screens. Furthermore, the apparatus may be placed in the basement or other suitable part of the dwelling and piped to the place or places where the gas is to be used. If desired, the gas regulator or expan sion valve 10 may be placed adjacent the apparatus in the basement, or it may be placed adjacent the heaters or gas stoves.

I claim:

1. In a liquid gas system comprising a source of liquid fuel supply under pressure and a pressure regulating valve throu h which liqid fuel is discharged from t e source of supply, an expansion tube into which the liquid fuel is discharged at a reduced pressure from the pressure regulating valve, said expansion tube having a series of spaced reticulated means therein through which the fuel is sprayed and progressively subdivided, and expanded.

2. In a liquid gas system, an expansion tube comprising an elongated tube closed at its ends by heads providing inlet and outlet openings, a series of spaced screens traversing the passage through said tube, and each screen comprising a disk-like wire mesh screen and inner and outer flanged clamping rings clamping the wire mesh screen between them and frictionally held within the tube.

3. In a liquid gas system having a pressure regulating valve for liquid fuel, a tube closed at its ends by heads, one provided with an inlet opening communicating with said pressure regulating valve and one provided with an opening communicating with a gas pipe, and a series of spaced Vfine mesh screen elements traversing the passage through said tube and secured to the wall thereof said screens serving to spray and progressively break up the fuel passing through the tube, the tube providing a chamber of relatively small dimensions for rapid expansion of the fuel therein.

STEPHEN S. THOMAS. 

